Alumina has properties useful in a wide variety of applications. Various techniques have been developed for alumina powder to provide, for example, transparent liquids containing alumina powder dispersed in water.
For example, Patent Literature 1 describes a technique associated with hydrated alumina particulate powder. In each of examples 1 to 10, a liquid was prepared by dispersing, in pure water, the hydrated alumina particulate powder to have an Al2O3 concentration of 2.2% by weight. Each liquid, measured with a spectrophotometer (at a measurement wavelength of 500 nm), showed a light transmittance of 30 to 32% (Table 2 in Patent Literature 1). The gel before spray-drying into the powder had a pH of 3.5 to 4.1 (Table 1 in Patent Literature 1).